Acoustic Consultants for London and the UK

PPG24 - Planning Policy Guidance 24: Planning and noise

The National Planning Policy Framework supersedes Planning Policy Guidance 24 – Planning and noise (PPG24), however PPG24’s assessment methodologies and the categorisation of sites using Noise Exposure Categories (NEC) remain in use by local authorities.

A PPG24  noise assessment is normally requested by a Planning Officer/Local Authority due to concerns relating to construction of new residential dwellings (or change of use) in a potentially high noise exposure area.

PPG24 Noise Assessments are requested because new dwellings can be exposed to road traffic, rail, air or mechanical/commercial noise which is unacceptable.

A 24 hour (longer may be required) noise assessment is conducted by an acoustic engineer in order to determine the Noise Exposure Category (NEC) that the proposed property would fall into.

This category would determine the level of noise mitigation measures e.g. glazing, ventilation etc. that would be required in order to provide satisfactory noise protection for the inhabitants.

PPG24 Reports include BS8233: 1999 simple or rigorous internal noise level calculations if required.

For further advice or assistance please email: or call the Sound Planning offices on 01252 711972.

To read more about PPG24 please visit the Local Government website (PPG 24).


PPG 24 Noise Assessment - Process

A class 1 (or Type 1) Sound Level Meter and environmental kit will be positioned on site.

[Sound Planning Kits include externally and internally mounted tripods]

Monitoring will normally occur over a 24 or 48 hour period (extended surveys are possible).

Broadband and single octave analysis will occur during the monitoring period.

Broadband measurements logarithmically formulate a daytime 0700 - 2300 hours (LAeq, 16h) and night time 2300 - 0700 hours (LAeq, 8h).

The broadband dB LAeq levels are classified within a Noise Exposure Category (NEC) A, B, C or D.

The differing NEC's correspond to varying levels of noise mitigation strategy e.g. Glazing, Ventilation, Facade Structure.

The single octave or frequency analysis is used in the calculation of glazing, ventilation and facade specification in accordance with BS8233: 1999.

All data relevant to the PPG24 Assessment will be compiled in an appropriate report which will be forwarded to the client and the local authority (if requested).

Sound Planning will liaise with the Planning Officer and Environmental Health Officer assigned to the application if requested by the client.

PPG24 Contacts 

Sound Planning Limited - Farnham, Surrey, Greater London.

Tel: 01252 711972